Morphology and related hemodynamics of the internal carotid arteries of moyamoya patients.

BACKGROUND

Morphological studies investigating the intracranial-extradural internal carotid artery with moyamoya disease have not been reported. We designed this case-control study to investigate the morphological differences of the internal carotid artery with moyamoya disease, and to clarify the contributions of these differences to the resultant fluid dynamics.

METHODS

Patients with moyamoya disease and normal controls were assigned to each group. The vascular tortuosity of internal carotid artery was measured with three-dimensional rendering using magnetic resonance angiography. By computational fluid dynamics, hemodynamic characteristics were simulated and compared between two groups.

RESULTS

Distances were measured from the carotid canal to the siphon. A shorter actual distance was observed in the moyamoya group (p = 0.0170). Vascular tortuosity was significantly low in moyamoya patients showing lower curvature angles in the petrous and intra-cavernous segments (p = 0.0012). Less blood flowed (p < 0.0001) through the narrower internal carotid artery (p < 0.0001) in the moyamoya group at the carotid canal level. The blood flow velocities were not significantly different (p = 0.2332). Faster blood flow and higher wall shear stress in the internal carotid artery bifurcation were verified with computational fluid dynamics.

CONCLUSIONS

Significant morphological differences were confirmed to exist in the intracranial-extradural internal carotid artery of moyamoya patients. These differences might influence the hemodynamics around the bifurcation of the internal carotid artery.